1. Field of the Invention
The present invention relates to sampling devices for the in viva acquisition of fluid samples from animals.
2. Discussion of the Prior Art
Many types of apparatus have heretofore been suggested for acquiring samples of the body fluids of animals. Similarly, many types of devices have been suggested for injecting fluids into the body of animals. Almost without exception, however, such sampling and injection devices have been designed for use in controlled-environment laboratory-type conditions. For example, when it is desired to sample the blood, or other body fluid of a bird, whale, fish, or other wild creature, the creature is captured and placed into a laboratory-type environment. The samples are then taken when the animal is in other than its natural habitat. This technique severely limits the type of experimentation which can be undertaken. Additionally, samples taken when the animal is in an unnatural laboratory-type environment may provide inaccurate physiological data.
When attempts are made to use the prior art laboratory-type sampling apparatus in the field, numerous difficulties result. In the first place, most of the prior art equipment is highly sophisticated and is not designed to withstand use other than in controlled laboratory conditions. Such equipment frequently fails when exposed to the rigors of field operations. Secondly, the instrumentation, and particularly, its related operational support equipment is quite complicated, difficult to transport and poorly adapted for field set up.
The unique apparatus of the present invention effectively overcomes the aforementioned drawbacks of prior art devices. It is rugged in design and although useful under laboratory conditions, is specifically adapted to permit in vivos sampling of the wild creature while freely moving about in its environment. Once affixed to the mammal or other animal, the device is fully automatic so that samples may be taken at predetermined times and at locations remote from the researcher. The apparatus can be used either for acquiring samples, such as blood, or for injecting fluids, such as anesthetics, into the creature. When used, for example, in studies of acquatic mammals, accurate analyses can be made of cardiovascular parameters and metobolic rates for both shallow and deep diving mammals. Due to the novel manner in which the fluid sample is stored in the apparatus, an accurate analysis can be made of dissolved gases in the body fluid of the creature. The apparatus is highly versatile and, in addition to permitting accurate analysis of dissolved gases, enables analysis of lactic acid and organic phosphates to determine how the increase in concentration of these substances alters with depth.
When the apparatus is used for sampling blood, its unique design permits retrieval of the sample at slow expansion rates by means of a metering valve. This enables more accurate corpuscle counts to be obtained by reducing the potential for damaging blood cells.
The apparatus is of a simple design and permits the use of unsophisticated field-worthy support equipment. It is, nevertheless, extremely accurate in operation and embodies a minimum number of moving parts thereby increasing its reliability and reducing its temperature sensitivity.
The apparatus of the invention can be used with equal proficiency either for sampling body fluids or for injecting fluids into the creature. When used in the study of wild animals, for example, one device can be used as a sampler and another as an injector. With the sampler, the desired sample of body fluid can be obtained. With the injector, anesthetics can be automatically injected into the animal so that the sampler can readily be recovered.
Applicant is familiar with the following prior art patents which represent the closest art known to applicant and which serve to illustrate the novelty of the invention as described and claimed herein.
U.S. Pat. No. 3,568,663 -- Phipps
U.S. Pat. No. 3,890,955 -- Elliott
U.S. Pat. No. 3,776,218 -- Svensson
U.S. Pat. No. 3,788,305 -- Schreiber